Apparatus for forming foil containers



S.J.HALTER pril 30, 1968 APPARATUS FOR FORMING FOlL CONTANERS 5 Sheets-Sheet l Filed Dec. 27, 1965 S. J. HALTER April 3o, 196s APPARATUS FOR FORMING FOIL CONTAINERS 5 Sheets-Sheet 2 Filed Dec. 27, 1965 April 30, 1968 s. 1. HALTER 3,380,272

APPARATUS FOR FORMKNG FOIL CONTAINERS Filed Dec. 27, 1965 5 Sheets-Sheet 5 United States Patent O 3,380,272 APPARATUS FOR FORMING FOIL CONTAINERS Stanley I. Halter, Mundelein, Ill., assigner to Kaiser Aluminum & Chemical Corporation, Oakland, Calif., a corporation of Delaware Filed Dec. 27, 1965, Ser. No. 516,330 7 Claims. (Cl. 72-57) This invention relates to an apparatus for forming a blank of relatively thin foil or foil-like material such as aluminum or aluminum alloy foil into a one-piece container having smooth wall surfaces and edges throughout. More particularly, this invention relates to an improved apparatus for forming a thin foil blank and the like into a container having smooth walls and edges wherein novel means are provided for smoothing and then positively clamping and sealing the marginal edge portions of blanks to elements of the apparatus in such a fashion as to facilitate the explosive drawing and elongating without wrinkling of the remaining or inner portions of the blank into the desired configuration.

Accordingly, it is the primary purpose of the instant invention to provide an improved apparatus for forming a thin metallic foil blank or the like into a relatively thin smooth walled container wherein the apparatus includes novel means for smoothing and then positively clamping and sealing the marginal edge portions of the blank to certain elements of the apparatus to facilitate the explosive drawing and elongating without wrinkling of the remaining or inner portions of the blank into the desired configuration.

This and other purposes and advantages of the instant invention will become more apparent from a review of the following detailed description when taken in conjunction with the appended drawings, wherein:

FIG. 1 is an overall sectional view of a preferred embodiment of the apparatus of the instant invention with the die parts of the apparatus being shown in an opened position and with a suitable control means for the apparatus being diagrammatically shown;

FIGS. 2 and 3 are sectional views on either side of the center line of the apparatus and illustrate the different operative positions of the apparatus in forming a blank into a container;

FIG. 4 is another partial sectional view of the apparatus and illustrates a further operative position of the apparatus with a completely formed container located therein;

FIG. 5 is a perspective view of a finished container that can be produced by the instant apparatus;

FIG. 5A is a fragmentary section taken generally along line SA-SA of FIG. 5;

FIG. 5B is a perspective view of a modified container that can be formed by the apparatus of the instant invention; and

FIGS. 6 and 7 are partial sectional views of a modified form of the apparatus of the instant invention illustrating different operative positions thereof.

With further reference to the drawings and particularly FIGS. 1-4, a preferred form of apparatus that can be used in carrying out the teachings of the instant invention generally comprises a die device 10. The device 10 includes a reciprocating ram generally indicated at 12 provided with a female die 14 at the forward end thereof. The lower portion of the die device 10 as shown in the drawings includes a platen or base generally indicated at 16. This platen cooperates with the ram 12 during the advancement thereof to form the inserted thin metallic foil blank or the like into a container of desired configuration such as a container illustrated in FIGS. 5 and 5A. A modified form of the apparatus of FIG. 1 is shown in ice FIGS. 6 and 7. In this instance the female die 14' has been slightly modified as will be set forth in detail hereinafter.

In forming this smooth wall container by the apparatus of the instant invention, a suitable control means is employed whereby the interrelated movements, to be subsequently described, of the ram 12, die 14 or 14 as the case may be, and portions of the platen 16 can be properly coordinated and synchronized. An appropriate control circuit 18 for effecting these movements is diagrammatically shown in FIG. 1 and although this circuit will be subsequently described with particular reference to the embodiment of the apparatus of FIG. 1 it is to be understood that the control circuit 18 can be used to equal advantage in the case of the modified embodiment of FIGS. 6 and 7.

Various types of thin metallic foil containers that can be formed by the apparatus of the instant invention are illustrated in FIGS. 5, 5A and 5B. The container W of FIG. 5 approximates the shape of a circular pie plate and includes a bottom planar wall B, the outer periphery of which intersects and merges with a frusto-conical side wall S that extends upwardly and outwardly to terminate in an outwardly extending flange F. The flange F acts as a reinforcing or container edge stiffening means and can be further reinforced by curling the edge of the diange into the shape shown in section in FIG. 5A. A rectangularly shaped container W is shown in FIG. 5B. This type of container includes a bottom planar wall B which merges with the planar side walls S that extend upwardly and outwardly to terminate in a reinforcing flange F. Each side wall S at its separate lines of intersection with other sidewalls S and the bottom wall B form corners having a generous radius. One of the distinctive characteristics of a smooth wall container formed by the apparatus of the instant invention is that the permanently stretched and deformed sections of the container, and comprised of the inner portion of the formable blank, such as the side and bottom walls of the container in FIGS. 5 or 5B, are relatively thinner than the flanged edge F or F thereof.

The ram 12 of the apparatus 10 in FIG. 1 is connected to a conventional supporting structure (not shown) of the forming apparatus 10 whereby the ram 12 can be advanced between the ends of the apparatus 10 by means of an actuator 20 which includes a iiuid actuated piston 22 connected to a piston rod 24. The exposed end of the rod is aixed to the body portion 26 of the ram 12. The forming end or draw ring 27 of the ram body 26 includes, as indicated in FIG. 1, a circular cutting edge 28 defined by the intersection between the outer cylindrical surface 30 and the annular end surface 32 of ring 27. The cutting edge 28 on the ram 12 cooperates with an opposed cutting edge on the platen 16 of the apparatus to sever a flat blank from a strip of material S" fed intermittently across platen 16y by suitable means (not shown) in a manner conventional in the art.

Mounted within the hollow interior of ring 27 is a female die 14. Die 14 is mounted in ring 27 so as to have limited axial movement relative to ring 27. To effect such movement, the interior of the ring 27 is provided With internal, cylindrical and concentrically arranged offset surfaces 34 and 36. These surfaces are interconnected by the radial shoulder 38 and surface 34 is of relatively greater diameter than surface 36. The forward end of surface 36 is interconnected to the inner end of the annular surface 32 of the ram lbody 26 by means of a partially toroidally shaped surface 40 which has been segmented in such a fashion that the concave portions of the segmented surface project inwardly and toward the platen end 16 of the apparatus. This partially toroidal surface 40 advantageously cooperates with a complementary surface of platen 16 as will be set forth hereinafter to form a reinforcing bead on the flanged edge of the container being formed.

The female die 14 advantageously comprises a pair Of slidably interfitted elements for movement in an axial direction relative to each other. More specifically, the female die 14 includes an outer draw ring 42 mounted for slidable movement relative to the bottoming die element 44. The inner surface 48 of the draw ring 42 is arranged in slidable surface-to-surface contact with the outer cylindrical surface 46 of the bottoming die element 44. Although not heretofore mentioned, the inner end of the interior cylindrical surface 34 at the forming ring or end 27 of the rant body 26 terminates against an intermediate plate Si) wherein the plate 5t) extends transversely of the rarn body 26 and acts as a backer plate for the form ing end 27 of the ram 12. The outer cylindrical surface 52 of the draw ring 42 is disposed in slidable surface-tosurface engagement with the interior and forward cylindrical surface 36 at the forming end 27 of the ram 12.

The bottoming die element 44 is resifiently suspended from the plate 50 of the ram body 26 as follows. A series of equally spaced openings 54 extend through the plate 50. Each end of each opening 54 is counterbored such that it is enlarged relative to the intermediate portion of the opening. A threaded cap screw 56 is passed through the counterbored openings 54 whereby its head end is disposed within one of the enlarged ends f an opening 54. A coil spring 60 surrounds the lower part of each cap screw 56 and is interposed within the other counterbored end of the opening 54 and the upper surface 61 of the bottoming die portion 44. Thus, the bottoming die element 44 is resiliently mounted relative to the intermediate plate 50 when the cap screw 56 is passed through the opening S4 so that the head of the screw 56 is located within the larger counterbore while the shank of the cap screw 56 passes through the opening S4 and the coil spring and into threaded engagement with threaded openings not shown within the bottoming die portion 44.

It is believed obvious from an inspection of FIGS. l-4 that downward movement of the bottoming die element 44 relative to plate 50 is limited by virtue of the contact between the head of the cap screws S6 and the radial shoulder of the larger counterbore at the upper end of the axial opening 54. The coil spring 60 advantageously limits the extent to which space between the bottoming die element 44 and the intermediate plate 50 is reduced when a load is imposed upon the -bottoming die element 44. Although only two openings 54 and two cap screws S6 and coil springs 60 are shown in FIG. l, it is to be understood that any number can be provided about the longitudinal axis of the apparatus to properly resiliently suspend or mount the bottoming die element 44 relative to plate t).

The forwardly projecting surfaces of elements 42 and 27 making up the female die 14 advantageously perform a dual function in that they act as blank forming as well as blank clamping and sealing surfaces. The forwardly projecting planar surface 62 of the bottoming die element 44 acts as a forming surface and extends laterally to intersect the inner surface 46 of ring 42. The draw ring 42 includes a frusto-conical forming surface 64 which extends downwardly and outwardly to intersect the lower annular surface 66. The annular surface 66 extends radially outward from its intersection with surface 64 t0 intersect the outer surface 52 of the draw ring 42. The upper end of the frusto-conical surface 64, however, intersects the inner surface 48 of the draw ring 42 at a point intermediate the length thereof. This forming surface 64 of the draw ring 42 advantageously cooperates with the forming surface 62 of the bottoming die portion 44 during operation of the device to form the inner portion of the workpiece W in a unique manner.

The draw ring 42 is yieldably urged to a forwardly extended position by the fluid biasing means described hereinafter. An annular flange 68 formed at the upper end of the outer surface 52 of the draw ring 42 is adapted to abuttingly engage the internal shoulder 38 of the forming ring 27 whereby the forward extent of the forwardly biased draw ring 42 wil be limited in accordance with the engagement of the flange 63 with the shoulder 3S. The aforementioned biasing means includes a closed pressure chamber 74 within which a free piston 76 is disposed and a series of freely mounted pins 82 extending through openings S4 in plate 50 and between the piston 76 and the upper annular surface 72 of the draw ring 42 for mechanically and loose`y interconnecting the piston 72 to the ring 42. The openings 84 have their centers spaced along a circumference, the center of which substantially coincides with the longitudinal axis of the apparatus. Thus, when uid under pressure is admitted by the conduit 148 of the control circuit 18 into the chamber 74 so as t0 act on the pressure side of the piston 76, the piston 76 and pins 82 act to yiedably maintain the draw ring 42 in a forward'y extended position whereby the flange 68 of the draw ring 42 is held in abutting contact with the shoulder 38 of ring 27.

Appropriate sealing rings 80 can be mounted in a suitable fashion within an appropriate opening in the periphery of the piston 76 in order to properly seal the piston 76 within the chamber 74 on the pressure side of the piston 76. Ath-ough only two pins 82 are shown in FIG. l, it is to be understood that any number of pins 82 can be used.

The upper outer periphery of the bottoming die element 44 is cut away in appropriate areas to dene inwardly extending recesses S6 for receiving each pin S2. Each recess 86 is so formed whereby the segmented cylindrical surfaces 88 thereof intersect the outer cylindrical surface 46 of the bottoming die element 44. The lower end of a segmented surface S8 is closed off by a transverse surface 90 of die element 44 while the upper end thereof intersects the upper surface 61 of the botoming die element 44. Thus, it is evident from an inspection of FIG. l of the drawings that with the draw ring 42 biased to a forwardly extended position and with the bottoming die portion 44 resiliently mounted as aforedescribed the forming surfaces 62 and 64 of the female die 14 are spaced a predetermined distance relative to each other prior to the full advancement of the ram 12 towards the platen 16. The relative displacement of the forming or backup surfaces or means 62 and 64 advantageously contributes to the forming of the workpiece as will be subsequently explained.

In order to permanently stretch and deform the inner portion of the blank against the forming surfaces 62 and 64 of the die apparatus by the explosive action of a controllably released compressed fluid during advancement of the ram 12, the outer peripheral portions of the blank are positively clamped and sealed between the advancing ram 12 and the platen 16. The annular end surface 66 of the draw ring 42 is disposed in general alignment with the outer periphery of the surface 104 of the inner platen element 96 whereby the advancing ram 12 causes the end surface 66 of the draw ring 42 and the directly opposed periphery of the platen surface 104 to be in positive clamping and sealing contact with opposite sides of the outer peripheral section of the marginal portions of the blank. This positive contact between blank and die elements occurs when the forward end of the advancing ram 12 is disposed immediately adjacent the strip S" being fed onto the platen 16 and is maintained until retraction of the ram 12 away from the platen 16. Buring the initial positive clamping and sealing contact of the marginal portions of the blank, no deformation of these portions occurs. As the ram 12 advances further about the platen 16, the draw ring 42 after initial contact with the outer periphery of the blank moves upwardly whereby the piston 76 interconnected to the ring 42 by the pins 82 as aforedescribed is forced upwardly to further compress the biasing fluid within the chamber 74. Compression of the biasing fluid results in bringing about operation of the control circuit 18 to be described for timely admitting the desired amount of fluid through line 122 against the underneath surface of the clamped blank so as to explosively stretch and permanently deform the inner portion of the blank by forcing the inner part of the blank against the forming surfaces 62 and 64 of the female die element 14.

The aforesaid upward movement of the ring 42 relative to the bottoming die element 44 and the interior of the ram 12 continues until the upper end surface 72 of the ring 44 abuts the circular ange or lip 76 (see dotted lines in FIGS. 1-4) formed on the upper outer periphery of the bottoming die element 44. Thereafter the ring 42 and bottoming die 44 act as a unit which is resiliently mounted to the intermediate plate 50 by the cap screws 56, etc. as aforedescribed. When the ring 42 and bottoming portion act as a unit, the forming surfaces 62 and 64 are brought in registery with each other such that the planar forming surface 62 now intersects the other forming surface 64 at its upper end and one surface in effect forms a continuation of the other.

The platen 16 on the other hand is made up of a series of interconnected elements, one of which moves relative to the other fixed elements whereby all portions of the platen 16 cooperate with the forming end 27 of the ram 12 to advantageously form the container W from a blank cut from the fed strip S. The platen 16 includes a base or bed 92, an outer ring 94, an inner bed plate 96 concentrically disposed and spaced radially inward relative to the outer ring 94 and an elevatable intermediate ring 98. The ring 98 not only moves relative to the ring and plate 94 and 96 but also cooperates with tbe forming ring 27 of the ram 12 during its advancement and retraction. The upper annular surface 100 of the outer ring 94 assists in the guiding of the strip S onto the platen 16 as shown in FIG. 1. It is to be understood, although not shown, that any suitable feeding mechanism can be used to feed a strip of foil material onto the platen 16. The inner peripheral edge 115 of the upper surface 100 of the ring 94 cooperates with the outer peripheral edge 28 of the forming ring 27 of the ram 12 to effect the initial severance of the blank from the strip S during a moment of dwell in the intermittent advance of strip S which is coordinated with the downward stroke of the press upon the advance of the forming end of the ram beyond the cutting edge 115 as shown in FIG. 2. The remaining portion of the severed strip S represents the next portion to be fed onto the platen 16 and then cut into a blank to be formed into a workpiece W.

The intermediate ring 98 is disposed for upward movement within a clearance space 107 defined by inner cylindrical surface 121 of ring 94 and by the series of outer peripheral surfaces of plate 96, namely, outer surfaces 113 and 120 and annular surface 114 extending between and connecting the inner ends of surfaces 113 and 120. The ring 98 is connected to the actuator 102 for limited movement within recess 107 relative to the platen elements 94 and 96. The actuator 102 comprises a closed cylinder for containing a piston 105 connected to rod 106. The rod 106 protrudes through the cylinder of the actuator and is connected to an intermediate plate member 108. A series of conventional lift pins 110 are affixed at one end to the member and at the other end to the ring 98. The pins 110 are spaced from each other in such a fashion that the longitudinal axes of the pins 110 are preferably disposed along a circle, the center of which coincides with the longitudinal axis of the rod 106. Each pin 110, in being alxed to the ring 98 and member 108, passes freely through an aligned cylindrical opening 111 provided in the support member 92. Although only two pins 110 are shown in FIG. 1, it is to be understood that any number can be used. When the ring 98 is disposed in its uppermost position by the actuator 102, the upper surface 116 of the ring 98 is in substantial planar alignment with the upper surfaces and 104 of the inner and outer platen elements 94 and 96 by virtue of the abutting contact between the lower annular surface 112 of the ring 98 and the annular shoulder 114 on the plate 96. Upon advancement of the ram 12, the forward surface 32 on ring 27 cooperates with surface 116 of the ring 98 to overcome the biasing action of the ring 98 and effect severance of the fed blank from the strip S as will now be described.

Severance of the blank from the strip S is attained by the cooperation of the cutting edge 28 on the forming ring 27 of the ram 12 and cutting edge 115 on the ring 98 upon the advancement of the forming ring 27 on the ram 12 into the clearance space 107. The diameter of the surface 30 of forming ring 27 is slightly less than the diameter of the inner cylindrical surface 121 of the outer ring 94 of the platen 16 so that there is ample room for sliding the surface 30 along surface 121 in order t0 effect efficient cutting of the strip S".

After initial severance of the strip S" into a container blank continued advancement of the ram into the clearance space 107 effects an advantageous folding and ironing of the marginal or peripheral edge of the blank along the inner surface 36 of the ring 27 and the outer surface i of the inner portion 96 of the platen 16 while the opposed annular end surfaces 32 and 116 of the ram 12 and ring 98 slidingly contact opposite sides of the marginal edge of the blank disposed therebetween. Sliding and somewhat smoothing contact of surfaces 32 and 116 relative to the marginal edge of the blank occu-rs due to the fact that the peripheral portion of the blank is at this time positively clamped and sealed as aforedescribed. During this relative sliding contact the marginal edge of the blank is progressively folded about the upper peripheral edge of the inner plate 96.

As indicated particularly in FGS. 2 and 3, further advancement of the ram 12 next effects ironing of the folded marginal edge portions between the cylindrical surface 120 of the platen inner portion 96 and cylindrical surface 36 at the forming end of the ram 12. In order to provide for merely folding and ironing the marginal edge of the severed blank, the diameters of the surfaces 36 and 120 are proportioned relative to each other to define a radially extending gap therebetween that substantially corresponds to the thickness of the marginal edge of the blank.

When the fully advanced ram 1'2 is initially retracted or withdrawn, the upwardly biased platen ring 9-8 maintains surface-to-surface contact between end surface 32 of the ram 12 and end surface 1116 of the ring 98 in order to effect curling of the ironed marginal edge of the severed blank. The shape of the surface 118 extending between the surfaces 116 and 11-7 on the ring 98 is toroidally complementary to the toroidally shaped surface 40 on the forming end of the ram 12 as aforedescribed. In other words, the toroidally shaped surface 118 of the ring 9'8 is of concave curvature in transverse section and is oppositely disposed to the toroidally shaped surface 4t) on the ram 12. The diameter off the inner surface 1'17 of the ring is slightly in excess of the diameter of surface 120` of the inner portion 96 of the platen so as to have sliding contact therewith. This sliding contact assures curling of the marginal edge to the blank within the complementarily shaped portions 40 and 11S upon retraction of the ram 12 and the biased upward movement of the platen ring 98 until the lower annular surface 112 of the ring 98 abuts the opposed annular surface 114 of element 96 as shown in FIG. 4. The curled edge to the workpiece W formed by the apparatus of the instant invention is shown in FIG. 5A.

To attain permanent stretching and deformation of the inner portion to the blank, a compressed gaseous iiuid is controllably and explosively admitted through a suitably bored passageway 122 provided in the inne-r plate 96 and element 92 of platen 16. One end of the passageway is assente connected to piping of the control circuit `18 while the other end of the passageway intersects the surface 11M of the platen plate 96 preferably at a point which coincides with the longitudinal axis of the apparatus. As gaseous fluid exits from passageway 122, it is directed against the underside of the interior portion of the blank prior to complete advancement of the ram 12 and while the outer marginal portions of the blank are clampingly and sealably engaged in a stepped or doulble folded fashion by the draw ring 4-2, ring 27 and plate 9'6 and ring 98. Inasmuch as the ram 12 has not 'been completely advanced at this time, the surfaces 62 and `64 of the die are displaced relative to each other and the blank is rst partially stretched yas shown in FIG. 2. Such partial stretching of the wor'- piece prior to alignment of the forming surfaces 62 and "64 has been found advantageous in order to effect forming of a relatively sharp radius between the intersection of the sidewall and bottom Wall of the workpiece W.

lthough not heretofore mentioned, to .assure proper permanent stretching and deformation of the inner portion of the workpiece W, appropriate intercommunicating openings, generally shown by dotted lines and indicated as V, are provided in the forming end 27 of the ram 12 and the bottoming die element 44. Thus, the vent openings V in the forming end of the ram 12 are disposed transversely of the apparatus and the other vent openings in the botto'ming die element are disposed longitudinally of the apparatus 10. It is believed to be readily apparent upon an inspection of FIGS. 1-4 that the openings V clearly and freely vent atmospheric conditions to the side of the formable inner portion of the workpiece W, facing directly lopposite the forming surfaces 62 and 64 of the die 14. Itis to be understood, even though only a pair of openings V is shown in the forming end of the ram 12 and the botto'ming die element 14, that any number can be used and arranged in any desired manner to effect satisfactory venting during permanent stretching and deformation of the workpiece W.

The principal operations which take place during a full operating cycle of the press and during the intermittent feeding of foil or foil-like material between the ram 12 and platen 16 are as follows. Firstly, a positive clamping and sealing of the marginal portions of the blank between the surface 66 of the draw ring 42 and the periphery of surface 104 of the inner platen portion 96 takes place. Secondly, a severing of the blank from the fed strip S" occurs as a result of the cooperative action of edges 2S and 115 of the ram 1-2 and platen portion 94. Thirdly, after severance of the blank, a folding and ironing of the marginal edge of the blank occurs due to the action of surface 36 of the ram 12 and surface 120 of the plate 96. Fourth, a partial stretching and deformation of the inner portion of the blank occurs due to explosive forcing of the blank against the surface 62 of the bottoming die portion 44 and prior to retraction of the biased draw ring 42 against the flange 70 of the bottoming die portion 44 as shown in FIG. 2. Fifth, a complete stretching and deformation of the inner portion of the blank occurs as a result of explosive forming of the blank against the surfaces 62 and 64 of the die when the draw ring 42 abuttingly contacts the ange '70. Finally, the folded and ironed marginal edge of the blank is curled back upon itself during retraction of the ram 12 by virtue of the end surface 1'16 of the upwardly 4biased platen ring 9S maintaining abutting contact with the end surface 32 of the ram 12 `whereby the toroidally shaped surfaces 40 and 118 cooperate to form the curled edge.

A suitable control system 1S for operating the press will now be described with the understanding that it is merely illustrative of one suitable control means that can be used. With reference to FIG. l, the control circuit 1S can include a cam shaft 124 driven by a motor 126. One end of the shaft 124 is anchored to a bearing support 128. Aiixed to cam shaft 124 in a series of spaced cams 13G, 132 and 134. Each cam 130, 132 and 134 operates in timed sequence to one another to control appropriate valve mechanisms 136, 138 and 140. Valve mechanism 1'36 is connected to a suitable source of air or uid under pressure by means of conduit also provided with an operator controlled inlet valve 142. When tripped by the cam, valve 136 directs the pressurized air from supply conduit 146 to either side of the piston 105 within the actuator 102 by means of interconnecting lines 142 and 144 in a well-known manner. As aforedescribed, the actuator 102 functions to bias the platen ring 98 to an upward position. Any excess of pressurized air within the lines 142, 144 and 140 can be directed into the exhaust line 146 by appropriate elements, not shown, in the valve 136.

The second cam actuated valve 138 is connected in parallel fashion across the air supply line 140 by means of supply line 142'. Prior to passage of the compressed air within supply line 142' through the valve 13S, the compressed air is directed to chamber 74 by interconnecting line 148 for further compression as aforedescribed. To prevent the further compressed fiuid from passing Iback into the supply line 142', a check valve 146 is disposed in the line 142 adjacent the connection of line 148. Upon operation of valve 138 by its associated cam 132, valve 138 admits a predetermined amount of further compressed uid from the chamber 74 to the platen passageway 122 for explosively forming or forcing the inner portion of the clamped blank against the forming surfaces 62 and 64 of the die plate 14 in the laforedescribed manner. In the event an excess of compressed fluid occurs in the line 159 or the supply lines 142 and 148, it is released through exhaust line 151 by appropriate means (not shown) provided Within the valve 138.

The remaining valve device 140 when properly actuated by its associated cam 134 supplies fluid under pressure to either side of the piston 22 within the actuator 20 for advancing and retracting the ram 12. Valve 140 is connected to a reservoir 152 by a conduit 154 having a fluid pump 156 disposed therein whereby the pump 156 directs uid under pressure from the reservoir 152 to the valve 140. Depending upon the particular position of the valve 140 Huid under pressure will be directed by the conduits 158 and 160 extending between the valve 140 and the actuator 20 to either side of the piston 22. Any excess fluid from conduits 158, 160 and 154 is directed yby appropriate means (not shown) within valve device 140 through the return conduit 162 extending between the valve mechanism 140 and the reservoir 152. Thus, it is evident that with the control circuit 18 having all cams 130, 132 and 134 properly coordinated for timely operating of the several valve mechanisms 136, 138 and 140 the forming apparatus 10 can be cyclically operated to form the smooth Wall container from the intermittently advancing strip S. It is also to be understood that the feeding mechanism for feeding the strip of material S" between the ram 12 and the platen 16 would be operated by suitable means (not shown) for fully synchronizing the operations of the control circuit 18 with the feeding of the strip S" to the press.

In the modified embodiment of FIGS. 6 and 7, it is to be understood that like parts are correspondingly numbered as in the aforedescribed embodiment of FIGS. 1-4. The embodiment of FIGS. 6 and 7 has been advantageously modified to incorporate a one-piece fem-ale die 14'. In other words, female die 14 has similarly shaped forming surfaces 164 and 166, but in this instance these surfaces comprise an integral part of the female die 14 instead of being formed of separate parts as is the case with the bottoming die element 44 and the draw ring 42 in the aforedescribed embodiments of FIGS. 1 4. Since the female die 14 is yof one-piece construction, it is only necessary to resiliently mount the die to a forwardly extended position relative to the forward end of the forming ram in a similar fashion as described in FIGS. 1-4. In order to effect this, die 14 is biasingly mounted within the ram 12 by the series of pins 82, only one of which is shown. These pins extend between the piston 76 and the upper surface 61 of the die 14. Forward movement of the onepiece die 14 is limited by a flange 68 abutting the internal shoulder 38 of the ram 12.

It has been found that the one-piece die 14', in forming the smooth wall container, does not form as sharp a radius between the side wall and the bottom wall as the aforementioned relatively sharp radius of the container produced by the two-piece die 14 of FIGS. l-4.

In the use of aluminum foil of .004" in thickness for producing the container of FIG. by the apparatus of the instant invention, approximately a 25% reduction in thickness of the explosively stretched and deformed or inner portion of the workpiece was attained without any fracturing of the foil. The average lateral dimension of the bottom wall of the container in FIGS. 5 or 5A produced by the apparatus is normally of relatively greater extent than the depth of the side wall.

In summary, it is to be understood that even though the aforedescribed embodiments relate to the formation of a contoured container of circular shape the container can have any desired shape even where the formed container is of rectangular shape as shown in FIG. 5B.

An .advantageous embodiment of the invention has been shown and described. It is obvious to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope thereof as set forth in the appended claims, wherein:

What is claimed is:

1. An apparatus for explosively forming a blank of relatively thin foil material and the like into a container of a selected configuration having substantially smooth walls and marginal edges comprising the combination of a reciprocating ram and a platen adapted to cooperate With the ram in forming the container, cooperating surfaces on the ram and platen for engaging and clampingly sealing the outer marginal portion of the container therebetween and from the atmosphere upon bottoming of the rarn, certain of said cooperating surfaces also being slidably arranged relative to each other whereby during actuation of said ram and prior to the bottoming thereof they will also effect an ironing and smoothing of the outer peripheral edge of said marginal portion and a bending of the outer peripheral edge of said outer marginal p0rtion relative to the remainder thereof, means for directing a fluid at a relatively high pressure and a relatively high velocity against one side as Well as the inner portion of the container during the clampingly sealed engagement of the marginal portion of the container with the said cooperating surfaces of the ram and platen to explosively form, and container backup means on the ram disposed in opposed relationship to said fluid directing means for engaging -and forming the inner portion of the container during the direction of the relatively high velocity uid under relatively high pressure thereagainst.

2. An apparatus as set forth in claim 1 including means of venting certain portions of the ram to the atmosphere during operation of the apparatus.

3. An apparatus as set forth in claim 1 including means located in the central portion of the platen for explosively directing said fluid against the one side and inner portion of the container.

4. An apparatus as set forth in claim 1 wherein said ram is provided with ring elements and said platen and ring elements have said certain of said cooperating surfaces.

5. An apparatus for explosively forming a blank of thin metallic foil and the like into a container of a predetermined conguration having substantially smooth walls and marginal edges comprising lthe combination of a reciprocating ram and a platen adapted to cooperate with the ram in the forming of the container, cooperating surfaces on the ram and platen for engaging and clampingly sealing the outer marginal portion of the container therebetween and from the atmosphere upon bottoming 0f the ram, certain of said cooperating surfaces also being slidably arranged relative to each other whereby during actuation of said ram and prior to the bottoming thereof they will also effect an ironing and smoothing of the outer peripheral edge of said marginal portion and a bending of the outer peripheral edge of said outer marginal portion relative to the remainder thereof, means located in said platen for directing uid at a relatively high velocity and a relatively high pressure against one side of as Well as against the inner portion of the container during the clampingly sealed engagement of the marginal portion of the container with the said cooperating surfaces of the ram and platen to explosively form, and means on said ram and platen for curling the edge of the container after the explosive forming thereof.

6. An apparatus as set forth in claim 5 including air means located in the central portion of the platen for eX- plosively directing said fluid against the one side of and inner portion of the container.

7. An apparatus as set forth in claim 5 wherein said ram is provided with ring elements and said platen and ring elements are provided Iwith said certain of said cooperating surfaces.

References Cited UNITED STATES PATENTS 2,284,773 6/ 1942 Sivian et al. 72-63 2,728,317 12/ 1955 Clevenger et al 72-60 2,899,922 8/1959 Wheeler 113-120 2,912,951 11/ 1959 Peters 29-421 2,968,270 1/ 1961 McChesney 72--354 FOREIGN PATENTS 1,012,378 12/ 1965 Great Britain.

RICHARD J. HERBST, Primary Examiner. 

1. AN APPARATUS FOR EXPLOSIVELY FORMING A BLANK OF RELATIVELY THIN FOIL MATERIAL AND THE LIKE INTO A CONTAINER OF A SELECTED CONFIGURATION HAVING SUBSTANTIALLY SMOOTH WALLS AND MARGINAL EDGES COMPRISING THE COMBINATION OF A RECIPROCATING RAM AND A PLATEN ADAPTED TO COOPERATE WITH THE RAM IN FORMING THE CONTAINER, COOPERATING SURFACES ON THE RAM AND PLATEN FOR ENGAGING AND CLAMPINGLY SEALING THE OUTER MARGINAL PORTION OF THE CONTAINER THEREBETWEEN AND FROM THE ATMOSPHERE UPON BOTTOMING OF THE RAM, CERTAIN OF SAID COOPERATING SURFACES ALSO BEING SLIDABLY ARRANGED RELATIVE TO EACH OTHER WHEREBY DURING ACTUATION OF SAID RAM AND PRIOR TO THE BOTTOMING THEREOF THEY WILL ALSO EFFECT AN IRONING AND SMOOTHING OF THE OUTER PERIPHERAL EDGE OF SAID MARGINAL PORTION AND A BENDING OF THE OUTER PERIPHERAL EDGE OF SAID OUTER MARGINAL PORTION RELATIVE TO THE REMAINDER THEREOF, MEANS FOR DIRECTING A FLUID AT A RELATIVELY HIGH PRESSURE AND A RELATIVELY HIGH VELOCITY AGAINST ONE SIDE AS WELL AS THE INNER PORTION OF THE CONTAINER DURING THE CLAMPINGLY SEALED ENGAGEMENT OF THE MARGINAL PORTION OF THE CONTAINER WITH THE SAID COOPERATING SURFACES OF THE RAM AND PLATEN TO EXPLOSIVELY FORM, AND CONTAINER BACKUP MEANS ON THE RAM DISPOSED IN OPPOSED RELATIONSHIP TO SAID FLUID DIRECTING MEANS FOR ENGAGING AND FORMING THE INNER PORTION OF THE CONTAINER DURING THE DIRECTION OF THE RELATIVELY HIGH VELOCITY FLUID UNDER RELATIVELY HIGH PRESSURE THEREAGAINST. 